The invention relates generally to the area of steel frame and concrete floor buildings and more particularly to a secondary steel framing member, in the form of a truss, in which the top chord of a specific configuration supports steel deck and acts as the shear connector in a composite system.
Composite design has been used in the construction industry for many years. The development and sophistication of economic structural systems has gradually extended to steel and concrete floor construction, the result of which has been to significantly reduce cost of steel framing in the industry. However, composite construction has generally been confined to primary wide flange or solid section members with stud-type shear connectors welded onto the top flanges in the field.
As those skilled in the industry are aware, conventional composite design consists essentially of three elements; that is, concrete, a steel beam or joist and a shear transfer mechanism. In the past, the shear transfer mechanism has usually been a stud shear-connector welded to the top flange of the beam and then the stud was encased in the concrete with the concrete slab generally above the plane of the top flange. Obviously, the shear-connecting device or stud, properly welded to the top flange of the beam, must be capable of resisting the shear force between the beam and the concrete to produce the desired composite action.
It will be appreciated that the purposes of composite floor construction are to save considerable steel weight and cost, as well as to reduce depth and deflection. While secondary framing members have been used in composite construction with steel decking, the manner of providing for shear transfer through use of the top chord of the secondary framing member has varied. Generally with respect to systems employing steel decking, the top chord of the secondary member has not been embedded in the concrete or the deck is not supported directly by the top chord, largely because of the varying specific designs or configurations of the top chords.
Among the prior art patents which are considered to be of interest with respect to the instant invention are U.S. Pat. Nos. 4,432,178; 4,295,310; 4,259,822; 4,056,908; 3,845,594; 3,728,835; 3,683,580; and 3,147,571. The patents just cited are directed to secondary member composite floor construction with steel decking but which neither individually nor in combination anticipate applicant's system.
The McManus patents for example show a combination joist and concrete composite system together with steel decking but are directed to features such as pan closures at the ends of the joists and protruding web apex portions as part of the shear transfer interconnection but without the top chord being embedded. Again, and as stated above, these references do not teach or suggest the combination of elements set forth in the claims herein. The Taft patent in FIG. 7 shows support of the decking on the bottom flange of a primary truss-type framing member. However, the instant application is directed to a secondary member with a configuration specifically designed to support steel deck.